Stable cosmetic formulation containing butylmethoxydibenzoylmethane

ABSTRACT

The invention relates e.g. to the use of aldehydes and/or ketones for improving the stability of cosmetic formulations containing butylmethoxydibenzoylmethane as organic light protection filters in conjunction with inorganic light protection filters.

[0001] The present invention relates, inter alia, to the use ofaldehydes and/or ketones for improving the stability of cosmeticformulations which comprise, as organic light protection filter,butylmethoxydibenzoylmethane combined with inorganic light protectionfilters.

[0002] As is known, the skin is sensitive to solar rays, which can causeordinary sunburn or an erythema, and also burns of greater or lesserseverity.

[0003] However, solar rays also have other adverse effects: they causethe skin to lose its elasticity and form wrinkles and these lead topremature ageing. Dermatoses may also sometimes be observed. In theextreme case, some people develop skin cancer.

[0004] It is also desirable to protect hair against photochemical damagein order to prevent changes in shade, bleaching or damage of amechanical nature.

[0005] As is known, the most dangerous solar rays are the ultravioletrays having a wavelength of less than 400 nm. It is also known that as aresult of the presence of the ozone layer in the Earth's atmosphere,which absorbs some solar radiation, the lower limit of the ultravioletrays which reach the Earth's surface is approximately 280 nm.

[0006] The sunscreen filters customarily used in cosmetics nowadays aredivided into UVA and UVB filters. For both UV ranges, there are manytried and tested substances known from the specialist literature,substances such as Eusolex® 6300 or Eusolex® 232, dibenzoylmethanes suchas Eusolex® 9020 (butylmethoxybenzoylmethane as UVA filter) or Eusolex®8020, benzophenones and also octyl triazones (Uvinul® T 150) beinglisted here merely by way of example.

[0007] However, the problem with many sunscreen preparations is thatmany light protection filters are sensitive substances and have lowstability towards ultraviolet rays; they break down at a greater orlesser rate. This results in problems with regard to shelf life andeffectiveness of the corresponding cosmetic formulations.

[0008] In sunscreen formulations organic light protection filters arealso combined with inorganic filters such as titanium dioxide, zincoxide or iron oxides. A frequently used organic light protection filteris butylmethoxydibenzoylmethane (BMDM). However, the effectiveness ofbutylmethoxydibenzoylmethane is significantly reduced in thiscombination with metal oxides as a result of the ability of thebutylmethoxydibenzoylmethane, as diketone, to form complexes with avariety of metal ions. Such reactions are known with ions of titanium,zinc, iron and aluminium. However, the metal ions do not primarily haveto be in the form of ions, but can also react in the form of oxides.These reactions are of course undesired in sunscreen formulations.

[0009] The object was therefore to find a way of preventing thisundesired reaction and thereby achieving an improvement in the stabilityof cosmetic preparations which comprise butylmethoxydibenzoylmethanetogether with inorganic light protection filters.

[0010] Surprisingly, we have now found that the undesired complexformation can be prevented by active aldehydes and/or ketones present.Here, the aldehyde and/or keto groups bond to the active sites of themetal oxide particle surfaces and thus prevent the possibility of theBMDM contacting with the metal oxides.

[0011] The invention thus provides for the use of aldehydes and/orketones for stabilizing cosmetic formulations which comprisebutylmethoxydibenzoylmethane combined with inorganic light protectionfilters.

[0012] The invention also provides a cosmetic preparation comprisinginorganic light protection filters and butylmethoxydibenzoylmethane,characterized in that aldehydes and/or ketones are added to improve thestability.

[0013] The invention further provides a process for improving thestability of cosmetic preparations comprisingbutylmethoxydibenzoylmethane combined with inorganic light protectionfilters, characterized in that aldehydes and/or ketones are added.

[0014] Suitable inorganic light protection filters are primarilytitanium dioxide, zinc oxide or iron oxides, and also cerium oxide. Inaddition, it is also possible for these oxides to be aftercoated withother metal oxides, for example with aluminium oxide.

[0015] The content of these inorganic particles in the formulationsaccording to the invention is 0.1 to 30% by weight, preferably 0.5 to10% by weight.

[0016] The butylmethoxydibenzoylmethane is represented in thepreparation according to the invention with a content of from 0.1 to 10%by weight, preferably from 0.5 to 3% by weight.

[0017] The BMDM can be present in the cosmetic formulations according tothe invention on its own or else in combination with one or more UVfilters from other classes of substance, each of which can be present inan amount of from 0.01 to 40% by weight, preferably from 0.1 to 10% byweight.

[0018] Suitable aldehydes or ketones are so-called active or activatedcompounds. Preference is given to using ketols, diketones or ketones oraldehydes which are in conjugation to a double bond, and alsoformaldehyde or formaldehyde-releasing substances.

[0019] By way of example, the following particularly preferred compoundsmay be mentioned: formaldehyde (also as formaldehyde-releasingpreservative), dihydroxyacetone, vanillin, erythrulose, hydroxyacetone,sugars, such as sorbose, fructose or glucose.

[0020] The content of aldehydes and/or ketones is at least 100 ppm andat most 10% by weight.

[0021] It is also possible to use combinations of aldehydes and ketones.In this connection, 1:1 combinations are preferably suitable. Forexample, a combination of formaldehyde and vanillin or of formaldehydeand erythrulose.

[0022] A very particularly preferred formulation according to theinvention comprises formaldehyde as aldehyde since this can, for thesake of simplicity, be used simultaneously as preservative.

[0023] The substance butylmethoxybenzoylmethane (Eusolex® 9020) is, asalready mentioned, known and can be obtained commercially, e.g. fromMerck KGaA, Darmstadt.

[0024] The aldehydes and ketones (or their precursors) can, on the onehand, be added directly to the cosmetic formulation, and on the otherhand it is also possible to admix or to wash the metal oxides with analdehyde or ketone as early as during their preparation, before they areadded to the cosmetic formulation.

[0025] For the effect according to the invention, this is of noconsequence.

[0026] The invention further provides a method of protecting the skinand/or natural or sensitized hair against solar rays, a cosmeticpreparation according to the present invention being applied to the skinor the hair.

[0027] “Sensitized hair” means hair which has been subjected to apermanent wave treatment, or to a colouring or bleaching process.

[0028] If the cosmetic preparation according to the invention is used toprotect the human epidermis from UV rays, it is in a variety of formscustomarily used for this purpose. For example, it can, in particular,be in the form of oily, oily-aqueous, aqueous-alcoholic oroily-alcoholic lotions, emulsions, such as a cream or milk (W/O or O/W,where W=water and O=oil), in the form of oily-alcoholic, oily-aqueous oraqueous-alcoholic gels or as solid sticks or powders, or can beformulated as a spray or aerosol.

[0029] The formulation according to the invention can comprise furthercosmetic additives which are customarily used in this type ofpreparations, such as thickeners, emollients, moisturizers, surfactants,preservatives, antifoams, perfumes, waxes, lanolin, propellants, dyesand/or pigments which colour the composition itself or the skin, andother ingredients ordinarily used in cosmetics.

[0030] The solubilizing agent can be an oil, wax or other fattysubstance, a lower monoalcohol or a lower polyol or mixtures thereof.Particularly preferred monoalcohols or polyols include ethanol,isopropanol, propylene glycol, glycerol and sorbitol.

[0031] A preferred embodiment of the invention is an emulsion which isin the form of a protective cream or milk and which, in addition toBMDM, optionally in combination with other organic light protectionagents, the inorganic light protection filters and the amount ofaldehydes and/or ketones according to the invention, comprises fattyalcohols, fatty acid esters, in particular triglycerides of fatty acids,fatty acids, lanolin, natural or synthetic oils or waxes and emulsifiersin the presence of water.

[0032] Further preferred embodiments are oily lotions based on naturalor synthetic oils and waxes, lanolin, fatty acid esters, in particulartriglycerides of fatty acids, or oily-alcoholic lotions based on a loweralcohol, such as ethanol, or a glycol, such as propylene glycol, and/ora polyol, such as glycerol, and oils, waxes and fatty acid esters, suchas triglycerides of fatty acids.

[0033] The cosmetic preparation according to the invention can also bein the form of an alcoholic gel which comprises one or more loweralcohols or polyols, such as ethanol, propylene glycol or glycerol, anda thickener, such as diatomaceous earth. The oily-alcoholic gels furthercomprise natural or synthetic oil or wax.

[0034] The solid sticks consist of natural or synthetic waxes and oils,fatty alcohols, fatty acids, fatty acid esters, lanolin and other fattysubstances.

[0035] If a preparation is formulated as an aerosol, use is normallymade of the customary propellants, such as alkanes, fluoroalkanes andchlorofluoroalkanes.

[0036] If a formulation is formulated as a spray, use is normally madeof aqueous-alcoholic solutions.

[0037] If the composition according to the invention is intended toprotect natural or sensitized hair from UV rays, then it can be in theform of a shampoo, lotion, mousse, gel or emulsion for rinsing out, therespective formulation being applied before or after shampooing, beforeor after colouring or bleaching, or before or after permanent waving; orthe composition is in form of a lotion, mousse or gel, for styling andtreating, a lotion, mousse or gel for brushing or setting a water-wave,a hairspray, permanent wave composition, colorant or bleach for thehair. Apart from the compound according to the invention, thiscomposition can comprise a variety of additives used in this type ofcomposition, such as surfactants, thickeners, polymers, emollients,preservatives, foam stabilizers, electrolytes, organic solvents,silicone derivatives, oils, waxes, degreasing agents, dyes and/orpigments which colour the composition itself or the hair, or otheringredients customarily used for hair care.

[0038] The cosmetic preparations according to the invention can beprepared using techniques which are well known to the person skilled inthe art.

[0039] The formulations according to the invention can also be used forthe preventative treatment of inflammations and allergies of the skinand for preventing certain types of cancer.

[0040] It is assumed that a person skilled in the art is able to utilizethe above description in the widest sense without further explanations.The preferred embodiments are therefore merely to be seen as adescriptive disclosure which is by no means limiting.

[0041] The examples below serve to illustrate the invention in moredetail. However, they are not suitable for limiting the subject-matterof the invention to these examples on their own.

EXAMPLE 1

[0042] The following components are used to prepare a sunscreen cream(O/W) according to the invention. % by wt A Eusolex ® 9020 (Art. No.105844) (1) 1.00 (Butylmethoxydibenzoylmethane) Arlatone 983 S (2) 1.50Arlatone 985 (2) 2.20 Brij 76 (2) 1.50 Miglyol 812 (neutral oil) (3)10.00 B Sorbitol F liquid (Art. No. 102993) (1) 2.50 1,2-propanediol(Art. No. 107478) (1) 2.50 Preservatives (1) q.s. Demin. water ad 100.00C Carbomer 934 (4) 0.50 D Tris (hydroxymethyl) aminomethane (1) 0.36(Art. No. 108386) Demin. water 9.64 E Eusolex ® T-2000 (Art. No. 105373)(1) 5.00 Formaldehyde solution (Art. No. 159174) (1) 0.10

[0043] Preparation:

[0044] Phase E is mixed and carefully stirred and dried. Phase B ismixed, Carbomer 934 is added thereto, and the mixture is left to swelluntil it is homogeneous. The premixed phase D is then added and themixture is homogenized. Phase E is then added to this mixture, which isthen heated to 80° C. Phase A is combined and heated to 75° C. With slowstirring, phase A is stirred into the phase prepared beforehand fromB-E.

[0045] Preservatives:

[0046] 0.05% of propyl 4-hydroxybenzoate (Art. No. 107427)

[0047] 0.15% of methyl 4-hydroxybenzoate (Art. No. 106757)

[0048] Sources of Supply:

[0049] (1) Merck KGaA, Darmstadt

[0050] (2) ICI, Essen

[0051] (3) Hüls Troisdorf AG, Witten

[0052] (4) Goodrich, Neuss

EXAMPLE 2

[0053] The following components are used to prepare a sunscreen cream(O/W) according to the invention. % by wt A Eusolex ® 9020 (Art. No.105844) (1) 1.00 (Butylmethoxydibenzoylmethane) Eusolex ® T-2000 (Art.No. 105373) (1) 5.00 Arlatone 983 S (2) 1.50 Arlatone 985 (2) 2.20 Brij76 (2) 1.50 Miglyol 812 (neutral oil) (3) 10.00 B Sorbitol F liquid(Art. No. 102993) (1) 2.50 1,2-propanediol (Art. No. 107478) (1) 2.50.Formaldehyde solution (Art. No. 159174) (1) q.s. Demin. Water ad 100.00C Carbomer 934 (4) 0.50 D Tris (hydroxymethyl) aminomethane (1) 0.36(Art. No. 108386) Demin. Water 9.64

[0054] Preparation:

[0055] Phase B is mixed, Carbomer 934 is added thereto, and the mixtureis left to swell until it is homogeneous. The premixed phase D is thenadded and homogenized. The mixture is then heated to 80° C. Phase A iscombined and heated to 75° C. With slow stirring, phase A is stirredinto the phase prepared beforehand from B-D.

[0056] Sources of Supply:

[0057] (1) Merck KGaA, Darmstadt

[0058] (2) ICI, Essen

[0059] (3) Hüls Troisdorf AG, Witten

[0060] (4) Goodrich, Neuss

1. Cosmetic preparation comprising inorganic light protection filtersand butylmethoxydibenzoylmethane, characterized in that aldehydes and/orketones are added to improve the stability.
 2. Cosmetic preparationaccording to claim 1, characterized in that the inorganic lightprotection filters present are titanium dioxide, zinc oxide or ironoxides, it also being possible for these to be aftercoated with othermetal oxides.
 3. Cosmetic preparation according to claim 1-2,characterized in that the aldehydes or ketones present are preferablyketols, diketones or those ketones or aldehydes which are in conjugationto a double bond, formaldehyde or formaldehyde-releasing substances. 4.Cosmetic preparation according to one or more of claims 1 to 3,characterized in that the content of butylmethoxydibenzoylmethane is 0.1to 10% by weight.
 5. Cosmetic preparation according to one or more ofclaims 1 to 4, characterized in that the content of aldehydes and/orketones is 100 ppm to 10% by weight.
 6. Cosmetic preparation accordingto one of claims 1 to 5, characterized in that the content of inorganiclight protection filters is 0.1 to 30% by weight.
 7. Use of aldehydesand ketones for the preparation of cosmetic preparations according toone or more of claims 1 to 6.